This invention generally relates to certain di-phthalonitrile monomors, to thermoplastic prepolymers and to thermosetting high temperature polymers therefrom. More specifically, this invention relates to di-phthalonitrile monomers, prepolymers and polymers which are solid at room temperature and which are devoid of ether and/or phenoxy groups.
Polymers of di-phthalonitrile monomers are high temperature materials which have a wide range of applications such as in composite materials, as adhesives, as sealants and as semiconductors. These polymers can be prepared from di-phthalonitrile monomers in which the linking group between the two ortho dinitrile groups separates the dinitrile groups enough to permit polymerization of the monomers. Presently, a number of bridging groups are known including aliphatic and unsaturated groups, aromatic groups, aliphatic and aromatic diamide and diimide groups, and aliphatic and aromatic ether, sulfone and ketone groups. For instance, --O--Ar--C.sub.3 F.sub.6 --Ar--O-- bridging groups are disclosed by Keller et al U.S. Pat. No. 4,238,601, --O--Ar--SO.sub.2 --Ar--O-- and --O--Ar--CO--Ar--O-- bridging groups are disclosed by Keller et al U.S. Pat. No. 4,234,712, --AR--S--A--S--AR-- bridging groups are disclosed by Keller et al U.S. Pat. No. 5,004,801, and many others. In the above bridging groups, Ar denotes an aromatic moiety and A denotes aliphatic and cyclic hydrocarbon moieties. The chemical and physical properties of the phthalonitriles depend primarily on the bridging groups.
Various bridging groups of imide-containing di-phthalonitriles are disclosed in Keller U.S. Pat. No. 5,003,078 and in U.S. Pat. No. 5,132,396.